#include <fstream>
using namespace std;
int m,n,s,a[100001][100001],VIZ[100001],Q[100001],p,u,v,i,j;

void BF( int i)
{
    p=u=1; Q[p]=i; VIZ[i]=1;
    while( p<=u)
    {
        v = Q[p++];
        for(j=1;j<=n;j++)
            if( a[v][j] == 1 && VIZ[j] == 0)
            {
                Q[++u] = j;
                VIZ[j] = 1;
            }

    }
 }

int main()
{
    int x,y;
    ifstream f("bfs.in");
    ofstream g("bfs.out");
    f>>n>>m>>s;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n;j++)
        {
            a[i][j]=100002;
            if(i==j) a[i][j]=0;
        }
    }
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        a[x][y]=1;
        a[y][x]=1;
    }
    BF(s);
}